PCem

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PCem
Screenshot of PCem running FreeDOS 1.0
Screenshot of PCem running FreeDOS 1.0
Developer(s) Sarah Walker (including contributors)
Initial release August 15, 2007; 11 years ago (2007-08-15)
Stable release
14 / April 20, 2018; 6 months ago (2018-04-20)
Written in C
Operating system Microsoft Windows, Linux
Type Virtual machine, emulator
License GNU GPL version 2
Website pcem-emulator.co.uk

PCem (short for PC Emulator) is an IBM PC emulator for Windows and Linux that specializes in running old operating systems and software that are designed for IBM PC compatibles. Originally developed as an IBM PC XT emulator, it later emulates other IBM PC compatible computers as well.

Unofficial builds of PCem are also available, such as 86Box, which includes a number of enhanced features, including SCSI and some new boards. Versions of PCem from v0.5 until v8 are not available for download, due to the use of the MAME OPL2 and OPL3 emulation code from when it was not yet licensed under a GPL-compatible license.

Features[edit]

Hardware[edit]

PCem is capable of emulating Intel processors (and its respective clones, including AMD, IDT and Cyrix) from Intel 8088 through the Pentium Tillamook MMX/Mobile MMX processors from 1997 until 1999. A recompiler has been added in v10.1, being mandatory for P5 Pentium and Cyrix processors and optional for i486 processors and IDT WinChip processors. Yet a rather fast processor is needed for full emulation speed (such as an Intel Core i5 at 4 gigahertz). However, the current developer of PCem has a main concern that the recompiler is not fast enough to emulate the Intel Pentium Pro/Pentium II processors yet.[1]

PCem emulates various IBM PC compatible systems/motherboards from 1981 until 1996, this includes almost all IBM PC models (including the IBM PS/1 model 2121 and the IBM PS/2 model 2011), some American Megatrends BIOS clones (from 1989 until 1994), Award BIOS systems (Award 286 clone, Award SiS 496/497 and Award 430VX PCI), and Intel Premiere/PCI and Intel Advanced/EV motherboards.[2] However, unofficial builds of PCem (PCem-X and PCem-unofficial) also supports IBM PC compatible systems/motherboards (from 1996 until 2000) that supports Intel Pentium Pro/Pentium II processors. PCem simulates the BIOS cache, which relies on the processor rather than on system memory.

PCem can emulate different graphic modes, this includes text mode, Hercules, CGA (including some composite modes and the 160x100x16 tweaked modes), Tandy, EGA, VGA (including Mode X and other tweaks), VESA, as well as various video APIs such as DirectX and 3Dfx's Glide. PCem can also emulate various video cards such as the ATi Mach64 GX, the S3 Trio32/64/Virge series and the 3Dfx Voodoo.

PCem also emulates some sound cards, such as the AdLib, Sound Blaster (including the Game Blaster), Sound Blaster Pro, Sound Blaster 16, Sound Blaster AWE32, Gravis UltraSound, Innovation SSI-2001, and Windows Sound System.[2]

Voodoo emulation is also emulated since PCem v10 and PCem v12, which added support for Voodoo 2 and various optimizations.[3] However, there some shortcomings regarding Voodoo emulation such as the lack of mip-mapping, slightly wobbling triangles, lack of speed limiting, and wrong refresh rates on almost every resolution (except 640x480@60 Hz).[4] As of PCem v11, a separate recompiler has been added for Voodoo emulation, making it faster to emulate the Voodoo graphics card.

An unofficial build of PCem allows to use SLiRP/WinPcap as a networking interface, plus emulated NE2000 and Realtek RTL8029AS Ethernet cards. However, starting with PCem v13, the emulation of NE2000 was officially added.

Operating system support[edit]

Similar to Virtual PC, Bochs and QEMU, it emulates almost all versions of Microsoft Windows until Windows XP (including Service Pack 3), MS-DOS, FreeDOS and CP/M-86 are also supported. Earlier versions of OS/2 requires the hard drive to be formatted prior to installation, while OS/2 Warp 3 until Warp 4.5 requires an unaccelerated video card to run. Other operating systems are also supported on PCem, such as versions of Linux that supports the Pentium processor, BSD derivatives (e.g. FreeBSD), and BeOS 5, which only works on the Award SiS 497 motherboard.

Version history[edit]

PCem version Release date Notes
v0.1 15 August 2007 Initial release.
v0.2 10 October 2007 Added Amstrad PC1640 and IBM PC AT emulation, 286 processor emulation, EGA/VGA video mode emulation, Sound Blaster emulation, hard disk emulation, plus some bugfixes.
v0.2a 14 October 2007 Minor bugfixes.
v0.3 30 July 2008 Added support for other 8088/286-based computers, plus emulation of Sound Blaster Pro and SVGA emulation, as well as minor additions.
v0.4 27 July 2010 Added preliminary Intel 80386/80486 emulation, Gravis UltraSound emulation, accurate 8088/8086 timings, and lots of other changes.
v0.41 1 February 2011 Bugfixes over v0.4.
v0.41a 13 February 2011 Fixed disc corruption bug, plus emulation of composite color display has been re-added.
v0.5 21 September 2011 Versions of PCem from v0.5 until v8 are not available for download, due to the use of the MAME OPL2 and OPL3 emulation code from when it was not yet licensed under a GPL-compatible license.
v0.6 19 December 2011
v0.7 3 August 2012
v8 20 December 2013
v8.1 3 January 2014 Fixed a number of issues in PCem v8. First version of PCem to replace the non-free MAME OPL2/OPL3 emulation code with a GPL-licensed OPL2/OPL3 emulation code.
v9 4 October 2014 Added IBM PCjr emulation and first version of PCem to have a Linux port, plus major changes and fixes.
v10 24 October 2015 Added AMI XT clone, VTech Laser Turbo XT, VTech Laser XT3, Phoenix XT clone, Juko XT clone, IBM PS/1 model 2011, Compaq Deskpro 386, DTK 386SX clone, Phoenix 386 clone, Intel Premiere/PCI, and Intel Advanced/EV emulation. Also adds support for Intel Pentium CPUs, 3Dfx Voodoo card emulation, plus various fixes and changes.
v10.1 7 November 2015
  • Fixed buffer overruns in PIIX and ET4000/W32p emulation
  • Added command line options to start in fullscreen and to specify config file
  • Fixed emulator crash when the CPU jumps to an unexecutable address
  • Removed Voodoo memory dump on exit
v11 5 June 2016
  • New machines added - Tandy 1000HX, Tandy 1000SL/2, Award 286 clone, IBM PS/1 model 2121
  • New graphics card - Hercules InColor
  • 3DFX recompiler - 2-4x speedup over previous emulation
  • Added Cyrix 6x86 emulation
  • Some optimisations to dynamic recompiler - typically around 10-15% improvement over v10, more when MMX used
  • Fixed broken 8088/8086 timing
  • Fixes to Mach64 and ViRGE 2D blitters
  • XT machines can now have less than 640kb RAM
  • Added IBM PS/1 audio card emulation
  • Added Adlib Gold surround module emulation
  • Fixes to PCjr/Tandy PSG emulation
  • GUS now in stereo
  • Numerous FDC changes - more drive types, FIFO emulation, better support of XDF images, better FDI support
  • CD-ROM changes - CD-ROM IDE channel now configurable, improved disc change handling, better volume control support
  • Now directly supports .ISO format for CD-ROM emulation
  • Fixed crash when using Direct3D output on Intel HD graphics
  • Various other fixes
v12 18 February 2017
  • New machines added - AMI 386DX, MR 386DX
  • New graphics cards - Plantronics ColorPlus, Wyse WY-700, Obsidian SB50, Voodoo 2
  • CPU optimisations - up to 50% speedup seen
  • 3DFX optimisations
  • Improved joystick emulation - analogue joystick up to 8 buttons, CH Flightstick Pro, ThrustMaster FCS, SideWinder pad(s)
  • Mouse can be selected between serial, PS/2, and IntelliMouse
  • Basic 286/386 prefetch emulation - 286 & 386 performance much closer to real systems
  • Improved CGA/PCjr/Tandy composite emulation
  • Various bug fixes
v13 11 December 2017
  • New machines added - Atari PC3, Epson PC AX, Epson PC AX2e, GW-286CT GEAR, IBM PS/2 Model 30-286, IBM PS/2 Model 50, IBM PS/2 Model 55SX, IBM PS/2 Model 80, IBM XT Model 286, KMX-C-02, Samsung SPC-4200P, Samsung SPC-4216P, Toshiba 3100e
  • New graphics cards - ATI Video Xpression, MDSI Genius
  • New sound cards added - Disney Sound Source, Ensoniq AudioPCI (ES1371), LPT DAC, Sound Blaster PCI 128
  • New hard drive controllers added - AT Fixed Disk Adapter, DTC 5150X, Fixed Disk Adapter (Xebec), IBM ESDI Fixed Disk Controller, Western Digital WD1007V-SE1
  • New SCSI adapters added - Adaptec AHA-1542C, BusLogic BT-545S, Longshine LCS-6821N, Rancho RT1000B, Trantor T130B
  • New network adapters added - NE2000 compatible
  • New cross-platform GUI
  • Voodoo SLI emulation
  • Improvements to Sound Blaster emulation
  • Improvements to Pentium timing
  • Various bug fixes
  • Minor optimisations
v14 20 April 2018
  • New machines added - Compaq Portable Plus, Compaq Portable II, Elonex PC-425X, IBM PS/2 Model 70 (types 3 & 4), Intel Advanced/ZP, NCR PC4i, Packard Bell Legend 300SX, Packard Bell PB520R, Packard Bell PB570, Thomson TO16 PC, Toshiba T1000, Toshiba T1200, Xi8088
  • New graphics cards added - ATI Korean VGA, Cirrus Logic CL-GD5429, Cirrus Logic CL-GD5430, Cirrus Logic CL-GD5435, OAK OTI-037, Trident TGUI9400CXi
  • New network adapters added - Realtek RTL8029AS
  • Iomega Zip drive emulation
  • Added option for default video timing
  • Added dynamic low-pass filter for SB16/AWE32 DSP playback
  • Can select external video card on some systems with built-in video
  • Can use IDE hard drives up to 127 GB
  • Can now use 7 SCSI devices
  • Implemented CMPXCHG8B on Winchip. Can now boot Windows XP on Winchip processors
  • CD-ROM emulation on OS X
  • Tweaks to Pentium and 6x86 timing
  • Numerous bug fixes

See also[edit]

References[edit]

  1. ^ "PCem • View topic - A mere idea for a future chipset (440FX)". pcem-emulator.co.uk. Retrieved 2016-08-08.
  2. ^ a b "PCem". pcem-emulator.co.uk. Retrieved 2016-08-07.
  3. ^ Cauterize. "Vintage Computer Emulator 'PCem' Now Running 3Dfx Based Windows Games". Retrieved 2016-08-07.
  4. ^ "PCem • View topic - 3DFX emulation". pcem-emulator.co.uk. Retrieved 2016-08-07.